Travis E L
Int J Radiat Oncol Biol Phys. 1984 Sep;10(9):1495-501. doi: 10.1016/0360-3016(84)90489-9.
This paper reviews the role of oxygen in the protection of both normal tissues and tumors in vivo by WR-2721. Although the presence of hypoxic cells in tumors is well accepted, data are presented that suggest there is a range of oxygen concentrations and thus OERs in normal tissues in vivo, too, and that some may, in fact, be radiobiologically hypoxic. Thus, the range of protection factors in normal tissues (which appears unrelated to tissue drug levels), as well as tumors can perhaps be explained by the range of OERs in these same tissues. The question of whether protection decreases with radiation dose per fraction is related to the distribution of oxygen in both normal tissues and tumors, i.e., whether oxygen is homogeneously or heterogeneously distributed among the cells. It is hypothesized that sulphydryl compounds may equalize the OER differential between tumors and normal tissues and thus remove the natural advantage (radioresistance) of the tumor when treated with radiation. Thus, no loss of therapeutic benefit would occur when sulphydryl compounds were given with radiation if the normal tissue were better oxygenated than the tumor.
本文综述了WR-2721在体内对正常组织和肿瘤的保护作用中氧气的角色。尽管肿瘤中存在缺氧细胞已被广泛接受，但有数据表明，体内正常组织中也存在一系列氧浓度，因而也存在一系列氧增强比，并且事实上有些组织在放射生物学上可能是缺氧的。因此，正常组织（这似乎与组织中的药物水平无关）以及肿瘤中的保护因子范围，或许可以用这些相同组织中的氧增强比范围来解释。保护作用是否会随着分次照射剂量的增加而降低这一问题，与正常组织和肿瘤中氧气的分布有关，即氧气在细胞间是均匀分布还是不均匀分布。据推测，巯基化合物可能会使肿瘤与正常组织之间的氧增强比差异趋于平衡，从而消除肿瘤在接受放射治疗时的天然优势（放射抗性）。因此，如果正常组织的氧合状况优于肿瘤，那么在给予放射治疗的同时给予巯基化合物时，治疗益处就不会丧失。
